Device for folding flaps of envelopes and the like



Aug. 6, 1968 P. SEYL. 3,395,624

DEVICE FOR FOLDING FLAPS OF ENVELOPES AND THE LIKE Filed Oct. 11, 1966 Inventor P 6 Z 58 ATTOILNGBs United States Patent 3,395,624 DEVICE FOR FOLDING FLAPS OF ENVELOPES AND THE LIKE Peter Seyl, Irlich (Rhine), Germany, assignor to Winkler & Dunnebier Maschinenfabrik und Eisen-Giesserei, Neuwied am Rhine, Germany, a firm of Germany Filed Oct. 11, 1966, Ser. No. 585,862 Claims priority, application Germany, Jan. 18, 1966, W 40,742 3 Claims. (Cl. 93-61) This invention relates to a device for folding flaps of envelopes, fiat bags and the like and refers more particularly to a device of this type which is used in an apparatus folding narrow flaps upon an already folded middle portion of an envelope for gluing the flap to the middle portion of the envelope.

In an apparatus of this type envelope blanks are moved through a machine and the folding lines of the flaps are usually scored in the direction parallel to the movement of the blanks prior to their folding. An apparatus of this type is described, for example, in the German Patent No. 836,431, in accordance with which the blank is introduced into the apparatus and then a large flap which extends transversely to the conveying direction is scored as well as two folds extending longitudinally relatively to the conveying direction. Thereupon gum is supplied to the middle portion of the blank, the middle portion is folded and then the bottom :fiap, which is already scored in the direction of movement of the blank, is folded upon the middle portion. Thereafter the bottom flap is re-opened, adhesive is applied thereto and then the bottom flap is folded again over the middle portion of the envelope and glued thereto. In existing devices of this type, particularly when they are used with heavy paper and the manufacture of powder-proof fiat bags the glue of which reaches almost up to the fold, it has been necessary to fold the narrow bottom flap of the envelope and then open it again, apply glue thereto and then refold it for gluing so as to make the fold line of the flap soft for the folding operation which is carried out by a strong folding knife and a curved arm. Thereupon the flap is opened again and after gumming, is folded once more with a very narrow thin folding knife. This procedure involved the folding of the flaps three times, with the result that the length of the machine must be increased to provide adequate distance for the folding.

An object of the present invention is to eliminate these complicated procedures and to provide an apparatus which is much shorter than those used heretofore, which will effectively fold and glue narrow flaps of envelopes, fiat bags and the like.

Other objects of the present invention will become apparent in the course of the following specification.

In the accomplishment of the objectives of the present invention it was found advisable to apply initially a layer of adhesive for gluing the flap to a wholly or partly folded middle portion of the envelope and to use a folding knife with an elongated groove-like recess located upon the underside of the knife so that the strip of adhesive can pass within that groove-like recess without contacting the knife. Thereupon a curved arm is used for folding back the flap upon the middle portion.

According to the present invention two opposed folding knives may be used which will hold down the gummed middle portion of the partly folded envelope and which will fold the two narrow side flaps extending in the direction of movement of the blank to be folded on the already folded middle portion of the blank and be glued thereto on an obliquely downwardly extending part of the machine. Such machine may :be otherwise constructed in the manner disclosed in the above German patent. It is not necessary to raise this portion of the machine for producing envelopes or bags with double side gluing. When a folding knife constructed in accordance with the present invention is used in the horizontally extending portion of the machine, the length of such a machine can be considerably shortened.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawing, showing by way of example, a preferred embodiment of the inventive idea.

In the drawing:

FIGURE 1 is a diagrammatic view showing a sequence of operations for folding and gluing a narrow flap of a blank and the tools pertaining thereto as they were used in prior art.

FIGURE 2 is a somewhat similar diagrammatic view illustrating the operations and the tools of the present invention.

FIGURE 3 is a longitudinal section along the line IH-III of FIG. 2.

FIGURE 4 is a transverse section along the line IV-IV of FIG. 2.

FIGURE 5 is an enlarged plan view of a folding knife of the type used in prior art.

FIGURE 6 is a plan view of a folding knife constructed in accordance with the principles of the present invention.

FIG. 1 shows a prior art apparatus wherein an envelope 1 is moved continuously in the direction of the arrow by any suitable conveying means, which are not illustrated. The envelope 1 is shown as having two side flaps 2 and 3 which have been already completely folded and glued together. The envelope also has a bottom flap B which has been already scored along the line 4 which thereafter will constitute the folding edge. However, at the extreme right side of FIG. 1 the flap B is shown as extending in the same plane as the middle portion of the envelope. The folding knife 5 is located directly above the path of the envelopes and is attached to a pin or holder 6 fixed to the casing of the machine. A curved arm 7 is located in the path of the bottom flap B of the blank and is supported by a pin or holder '8 which is also attached to the machine casing.

The curved arm 7 is similar to the curved arm 27 of the present invention which is illustrated in FIG. 2 and 4.

As the envelope blank moves through the machine the flap B is moved slightly above the end 7' of the arm 7. As the blank continues its movement the flap B is further engaged by the arm 7 and is moved upwardly into the position B1 around the edge of the folding knife 5 which lies above its score line. Then the flap is completely folded over the middle section of the envelope blank as indicated at B2. Thereupon the flap encounters an arm 9 which extends in the opposite direction to the arm 7. The arm 9 is attached to the machine casing by a pin or holder 10. The arm 9 extends between the flap and the central portion of the envelope blank so that the flap in the position B3 is half opened by the arm 9. As the envelope blank continues its movement the flap is completely opened by the arm 9 as indicated at B4. As the flap moves from the position B4 to the position B5 a strip of adhesive 11 is applied in the usual manner to the flap. Then the envelope blank encounters a third arm 12 fixed upon a holder or pin 13. The arm 12 first raises the flap to the position B6 and then finally folds the flap with the adhesive thereon as indicated at B7. It should be noted that the arms 7 and 12 are similar to each other. During the last portion of the movement of the blank a second folding knife 14 is used which has a rear end 16 thinner than the rear end of the folding knife 5 (FIG. 5). This construction is necessary since the rear end 16 of the folding knife 14 must become thinner as the adhesive 11 on the flap reaches its fold line so as to avoid smearing the adhesive.

This complicated prior art procedure has been greatly simplified in accordance with the construction of the present invention.

FIGS. 2, 3 and 4 show diagrammatically the use of the device of the present invention. A blank 20 is initially provided with a strip of adhesive 21 in the usual manner. The center portion of the blank has already been folded but it is provided with a flap B8 extending in the plane of the central portion. In accordance with the present invention a folding knife 22 is used which is attached to the casing of the machine by a pin or holder 23. The folding knife 22 is located directly above the path of the envelope blank moving in the direction of the arrow. The underside of the folding knife 22 has a longitudinal groove 24 which extends in the direction of movement of the envelope blank and which has the edges 25 and 26. When the envelope blank moves under the folding knife the strip of adhesive 21 passes through the groove 24 without touching the knife. On the other hand, the edges 25 and 26 of the folding knife hold down the envelope blank securely during its passage (FIG. 4). A curved arm 27 which is supported by a pin or holder 28 is associated with the folding knife. The flap B8 has been previously scored along its folding edge and as the blank moves through the machine the arm 27 raises the flap to the position B9 and then folds it over the glue 21 upon the central portion of the blank as indicated at B19. Thereafter rollers (not shown) are used to press the flap firmly against the envelope.

It is apparent that the procedure of the present invention makes it possible to greatly diminish the size of the folding machine. The strong folding knife 22 constructed in accordance with the present invention makes it possible to fold narrow flaps of large envelopes made of heavy stiff sulfate paper in a single folding operation. The operational speed is greatly increased.

On the other hand, the prior art folding knife 14 shown in FIG. 5 must be provided-with such a thin end 16 that heavy and stiff paper must be folded in the manner shown in FIG. 1 on a longer prior art machine requiring a number of additional steps which have been eliminated by the present invention.

It is apparent that ditferent variations and modifications can be made in the illustrated example without exceeding the scope of the present invention.

What is claimed is:

1. In an apparatus for folding a scored flap of a movable envelope or the like over a glue-carrying portion of the envelope, a folding knife engaging said envelope and having a recessed portion extending in the direction of movemerit of said envelope, said glue-carrying portion moving into said recessed portion and then emerging out of said recessed portion without contacting said knife during the movement of said envelope, and a curved arm extending adjacent said folding arm and engaging said flap during the movement of said envelope for raising said flap and then folding it over said glue-carrying portion after the glue-carrying portion emerged out of said recessed portion.

2. An apparatus in accordance with claim 1, wherein said curved arm raises said flap during its movement through the recessed portion.

3. An apparatus in accordance with claim 1, having two folding knives and two curved arms located on opposite sides of said envelope.

References Cited UNITED STATES PATENTS 1,774,536 9/1930 Winkler et al. 93--6l BERNARD STICKNEY, Primary Examiner. 

1. IN AN APPARATUS FOR FOLDING A SCORED FLAP OF A MOVABLE ENVELOPE OR THE LIKE OVER A GLUE-CARRYING PORTION OF THE ENVELOPE, A FOLDING KNIFE ENGAGING SAID ENVELOPE AND HAVING A RECESSED PORTION EXTENDING IN THE DIRECTION OF MOVEMENT OF SAID ENVELOPE, SAID GLUE-CARRYING PORTION MOVING INTO SAID RECESSED PORTION AND THEN EMERGING OUT OF SAID RECESSED PORTION WITHOUT CONTACTING SAID KNIFE DURING THE MOVEMENT OF SAID ENVELOPE, AND A CURVED ARM EXTENDING ADJACENT SAID FOLDING ARM AND ENGAGING SAID FLAP DURING THE MOVEMENT OF SAID ENVELOPE FOR RAISING SAID FLAP AND THEN FOLDING IT OVER SAID GLUE-CARRYING PORTION AFTER THE GLUE-CARRYING PORTION EMERGED OUT OF SAID RECESSED PORTION. 